Conventionally, radar apparatuses are known, which are capable of detecting a region where a rain/snow reflection signal is generated, by discriminating the rain/snow reflection signal from a signal obtained from a target object (e.g., a ship or land). JP2010-181335A discloses this type of a radar apparatus.
The radar apparatus of JP2010-181335A transmits radio waves while rotating an antenna and generates a radar image based on reflection waves caused by the transmitted radio waves, and includes a receiver and a rain/snow reflection determining module. The receiver receives the reflection waves caused by the transmitted radio waves. The rain/snow reflection determining module determines whether the signals received by the receiver are rain/snow reflection signals by using a variation of the signal level (echo intensity) per unit of a given distance, azimuth, or a combination thereof.
Further, in Paragraph [0052] etc. of JP2010-181335A, a configuration is disclosed in which the levels of the reception signals determined as the rain/snow reflection signals by the rain/snow reflection determining module are suppressed so that when displayed, the levels (echo intensities) of the reception signals are not reflected as they are in corresponding pixels to a rain/snow reflection region on the radar image. Moreover, in FIG. 9 of JP2010-181335A, an image example in which only the rain/snow reflection region is extracted on the radar image is disclosed.
However, with the configuration of JP2010-181335A, although the reflection waves in the rain/snow reflection region can effectively be suppressed, the existence of rain or rain cloud is not displayed here. Therefore, to a user who wants to obtain information of rain or snow, there still is a room for improvement.